2002 November, Vol 50 Number 11

CONTENT

PAPERS

Estimation of Modal Decay Parameters from Noisy Response Measurements
Matti Karjalainen, Poju Antsalo, Aki Mäkivirta, Timo Peltonen, and Vesa Välimäki   867
Estimating decay parameters, such as room reverberation or string decay of musical instruments, becomes more inaccurate as the noise level increases if that noise is not also included in the parametric model. A new method based on nonlinear optimization of a linear model with additive noise is demonstrated as being more accurate than the traditional approaches, especially at extreme noise conditions. Several practical examples illustrate the utility of the proposed method.

On the Use of Time-Frequency Reassignment in Additive Sound Modeling
Kelly Fitz and Lippold Haken   879
The conventional short-time spectral analysis is unable to parameterize signals that have both narrow-band components combined with transients because of the nature of the time-frequency definition. Moreover, a single musical partial, which often has time-varying amplitude and frequency envelopes, does not appear as a single component in the classical linear analysis approach. By reassigning energy components, temporal smear is greatly reduced because unreliable data points can be removed from the representation. Several examples illustrate the ability to reconstruct abrupt onset square waves.

Scalable Multichannel Coding with HRFT Enhancement for DVD and Virtual Sound Systems
M. O. J. Hawksford   894
Using the perceptual properties embedded in the head-related transfer functions of a normal listener, a standard five- or six-channel audio source can be transformed to feed additional loudspeakers, perhaps as many as 18. The proposed system enhances image stability by optimizing the correct ear signals at the listener's location. The approach improves spatial resolution over a wider area while retaining backward compatibility with an unprocessed reproduction environment.

Two-to-Five Channel Sound Processing
R. Irwan and Ronald M. Aarts   914
In order to reproduce two-channel audio sources in a surround listening environment, the authors evaluated a proposed processing system based on decoding the principle directional component using correlation techniques. By parameterizing direction a stable center channel was created. Moreover, the synthesized ambiance for the sides does not degrade image stability.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News   927
New Internet facilities; preservation of recordings; storage and handling; audio connectors; grounding and shielding; file exchange

FEATURES

113th Convention Report, Los Angeles   934
     Exhibitors   950
     Program   954
Bluetooth and Wireless Networking-A Primer for Audio Engineers   979
11th Tokyo Regional Convention, Call for Papers   1001

DEPARTMENTS

News of the Sections   985
Sound Track   989
Upcoming Meetings   990
New Products and Developments   990
Available Literature   992
Membership Information   993
Advertiser Internet Directory   999
In Memoriam   1000
Sections Contacts Directory   1002
AES Conventions and Conferences   1008

FPO For the cover:

2002 November, Vol 50 Number 11

spine: 2002 November, Vol 50 Number 11